Your story, however amusing, is somewhat clouding the point of the CB discussion on the
node in question. Who will
make the best engineer in your story? Probably number four. Who will get
the best mark on the assignment? That isn't clear as we don't
know which course this is for (e.g. theoretical or experimental), but we can be pretty confident that it
won't be number four.

I'm not sure about morals, but personally I don't feel it is useful or
helpful to give a student the answers directly. On the other
hand, I'm not sure how many professionals are literally paid to know
the answer as part of their job. Know how to find the answer? Sure. Know
how to ask the right questions? Even more important. But knowing all the
answers isn't part of many job descriptions. To take that to an
extreme that person would have to have memorised all applicable manuals in
the field, as well as not needing to ask a peer for assistance. I don't want
someone that confident working for me as I'd always have to check that they
were in fact correct and not just overconfident (which is much more common IME).

And for the record, as a former long-time engineering student I can
attest to the fact that questions were very often mis-numbered! ;-)